Polymerization of norbornene and alkenyl-norbornenes catalyzed by palladium-benzyl or nickel-aryl complexes: Effects in polymer structure and application as catalyst support

Abstract

The vinylic addition polymerization of norbornene produces a type of polymer (VA-PNB) which keeps the bicylic structure of norbornene and has a completely aliphatic skeleton. It has got attractive properties, such as thermal and chemical stability, ideal for some applications as materials or in the field of heterogenous catalysis as support. Our group has made in the past contributions to the synthesis of functionalized VA-PNBs and their use in catalysis. This thesis is a step further and collects the results obtained in the VA-polymerization of alkenyl-norbornenes, leading to substituted polymers with pendant double bonds that are very useful starting materials to introduce other functional groups in the polymer. The most representative catalysts for the synthesis of VA-PNBs are complexes of the late transition metals, such as Ni(II) and Pd(II). Among them, a special category are the complexes that can initiate the polymerization without the presence of an additional co-catalyst and therefore show in their structure a M-R bond where R = allyl, alkyl, aryl or H. In this thesis two types of complexes with M-R bonds were employed for the synthesis and mechanistic studies on the vinylic addition polymerization of norbornene and their derivatives. The goal was not only to develop new active catalysts for this reaction but also to understand certain unprecedented features of the polymerization mechanism.